I personally can't get the sound volumes the way I'd like them.
Car sounds seem too low, cinematic sounds like in the race start cut-scenes with the cheesy and unnecessary burnout are too high, so that even if I tune down all sounds to be able to crank up my speaker volume for higher engine sounds, I end up with super loud cut-scene effects.
Also, please add an easy to access radio volume slider? I mean radios come with volume keys for a reason.